POWER RANKINGS: Here's who has the best chance at being the next US president

In less than a week, the first votes of the 2016 presidential primary will be cast in the Iowa caucuses.

Heading into the final Republican debate Thursday night before the caucuses, insurgent “outsiders” from both parties have made their mark on the already extensive primary process.

On the Republican side, businessman Donald Trump finds himself in perhaps his strongest position yet, leading all national polls and most surveys of the early states of Iowa, New Hampshire, South Carolina, and Nevada.

This comes from a candidate who was largely expected to wane as the summer, let alone fall, let alone winter, went on.

In the Democratic primary, meanwhile, Sen. Bernie Sanders (I-Vermont) has surged of late. He is poised for potential upsets of the front-runner, former Secretary of State Hillary Clinton, in the first two voting states of Iowa and New Hampshire. Clinton still holds a sizeable, if shrinking, national poll lead.

Our rankings are based on the Real Clear Politics averages of national polls and those in the first-voting states of New Hampshire, Iowa, and South Carolina. We also factor in candidates’ fund-raising prowess and their momentum (or lack thereof) over the past few weeks.

Here’s a look at where all the candidates stand.

(All poll results as of Tuesday.)

14. Rick Santorum, Republican, former senator from Pennsylvania

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It's sometimes easy to forget that Santorum won 11 states in his 2012 primary matchup with Mitt Romney, the eventual Republican nominee -- including the Iowa caucus.

That's because he still hasn't even been a blip on the radar in the 2016 race.

He is facing stauncher competition this time around, and he has not solved his biggest problem from 2012: money. He raised less than $400,000 in third-quarter fund-raising and had just more than $200,000 in cash on hand, the kind of money that doesn't bode well for staying power in a crowded field.

The state that provided his biggest win in 2012, Iowa, also hasn't given him the same kind of love. Despite focusing on the Hawkeye State, he still barely registers in polling there, placing 11th in an average of recent polls. He has lingered around that level since he entered the race.

National polling average among Republican voters: 0.2% (11th)

Iowa: 1% (11th)

New Hampshire: 0.2 (11th)

South Carolina: 0.5% (11th)

STOCK: Neutral

Last month: 14

13. Martin O'Malley, Democrat, former Maryland governor

ABC

Martin O'Malley.

O'Malley has watched as Bernie Sanders has entrenched himself as the progressive alternative to Hillary Clinton, outflanking O'Malley's attempts to outflank Clinton from the left.

Despite a vigorous campaign schedule, O'Malley is still not well known nationally, and he has been unable to boost his poll numbers even in a three-way race.

O'Malley has an accomplished progressive record as governor, with achievements -- on immigration, criminal justice, same-sex marriage, and healthcare, among others -- that he can legitimately tout to Democratic voters. But he hasn't been able to break out of the doldrums.

National polling average among Democratic voters: 2.2% (3rd)

Iowa: 4.3% (3rd)

New Hampshire: 2.6% (3rd)

South Carolina: 1.5% (3rd)

STOCK: Falling

Last month: 13

12. Mike Huckabee, Republican, former Arkansas governor

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Former Arkansas Gov. Mike Huckabee (R).

Huckabee has continued an attempt to endear himself to conservative, evangelical voters. But he's clearly falling short.

The first part of his presumed theoretical path to the nomination -- winning Iowa, the state he captured in 2008 -- is in serious limbo. He polls just eighth in the Hawkeye State, and he has kept slipping there continually over the past two months.

This Republican field may be too crowded for a candidate like Huckabee. He is extremely popular with evangelical conservatives, but many of those conservatives look as if they're flocking to candidates such as Trump and Sen. Ted Cruz (R-Texas).

National polling average among Republican voters: 2.5% (T-7th)

Iowa: 2.2% (8th)New Hampshire: 0.7% (10th)

South Carolina: 2% (T-9th)

STOCK: Falling

Last month: 11

11. Carly Fiorina, Republican, former Hewlett-Packard CEO

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Fiorina surged after she stole the show with a stunning performance during the first lower-tier Republican debate in August.

But over the past few months, she has had trouble sustaining that magic amid more scrutiny. She has dipped from her third-place standing in national polls at the height of her climb to just ninth now. She has fallen again from the main debate stage to the 'undercard' affair.

Still, she has experience as a business executive that few others in the field can point to, and she has been one of Hillary Clinton's fiercest critics.

10. Rand Paul, Republican, senator from Kentucky

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Paul climbed back onto the main debate stage after a publicity — and poll — boost that followed his decision to skip the latest 'undercard' debate.

Still, he has not been able to break through from his initial plunge over the summer and early fall. Of particular note is his drop in Iowa, where he has fallen from second (9.8%) in July to fifth (3.8%) now. (His fifth-place standing in Iowa, however, was good enough for a place on the main Fox News debate stage.)

He has to hope he continues to build momentum — he also has a Senate reelection to start thinking about.

But his time in the intense spotlight looks as if it might have finally taken its toll. He has dipped back to fourth place nationally and in Iowa, as scrutiny over his potential as commander-in-chief has piled up, as he has seen more established candidates like Cruz and Sen. Marco Rubio (R-Florida) rise. And his campaign has been thrown into disaster with the resignation of top aides..

His national poll numbers have dipped about 17 points over the past three months.

National polling average among Republican voters: 7.8% (4th)

Iowa: 7.2% (4th)

New Hampshire: 3.3% (9th)

South Carolina: 9% (5th)

STOCK: Falling

Last month: 7

8. Chris Christie, Republican, New Jersey governor

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Christie has seen a bit of momentum sapped over the past month in the first-primary state of New Hampshire, where he is counting on a strong finish and where he has put in the most time of any GOP candidate.

Amid a barrage of attacks from rival candidates and their allied interests, Christie has seen his poll standing in the Granite State dip about 4 points over the past month. He's now sixth there, compared with fourth last month.

Christie, however, has appeared to benefit overall from an increased focus on national security after the terrorist attacks in Paris and San Bernardino, California. But with a crowded, establishment-minded field all battling to finish second to Donald Trump, it's unclear whether Christie can recover.

7. John Kasich, Republican, Ohio governor

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Kasich is the biggest mover in this month's power rankings, jumping to seventh from 11th after a fresh surge in New Hampshire.

He has overtaken Marco Rubio in the state and sits third behind Donald Trump and Ted Cruz. There's a legitimate chance he could come out on top of a clustered bit of Republican establishment-type candidates.

Those who talk up Kasich believe he is a Christie-type without the baggage of the past year and a half — that is, a successful governor with a record to point to and clear bipartisan appeal. He also has a plethora of experience from serving nearly two decades in Congress, including foreign-policy areas and his time as chair of the US House budget committee.

But that same bipartisan brand could hurt Kasich with the GOP base. He is to the left of most GOP candidates on immigration reform, and he expanded the federal Medicaid program under the Affordable Care Act — two issues that could doom him with hard-line conservatives.

6. Bernie Sanders, Democrat, senator from Vermont

Sanders is another big mover in our power rankings — and he has a legitimate shot to provide shocking upsets to Hillary Clinton in both Iowa and New Hampshire.

Sanders is peaking at the right time. His momentum, and the grassroots support and donations behind it, have evoked comparisons to the 2008 rise of Barack Obama, then an Illinois senator.

But Sanders still faces daunting challenges against the behemoth that is Clinton and her campaign. There are questions about whether he's a legitimate threat in the long haul and about his viability as a potential nominee in a general election.

Still, if he captures victories in the first two voting states, the door to the nomination that was long thought closed could creak even more open.

5. Jeb Bush, Republican, former Florida governor

Graham Flanagan/Business Insider

Bush, once viewed as the clear front-runner, has seen Trump sap the momentum he had built after his official campaign announcement in June. His poll numbers have slumped across the board -- his 17% national average in July has dipped 12 points over the past six months.

It's starting to pay off, as he has seen a slight poll bump over the past month nationally and in the key state of New Hampshire.

Bush has showed, too, that he is a dynamic fund-raiser. And he retains significant resources that could prove to be a game changer in the long haul.

National polling average among Republican voters: 5% (5th)

Iowa: 3.7% (6th)

New Hampshire: 8% (5th)

South Carolina: 10.5% (4th)

STOCK: Rising

Last month: 5

4. Marco Rubio, Republican, senator from Florida

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Off strong early debate performances, Rubio quickly became a rising establishment favorite for the Republican nomination.

But he has stagnated somewhat over the past two months. Ted Cruz has surged far ahead of him in Iowa. Kasich has surpassed him in New Hampshire, and Bush and Christie are nipping at his heels. Nationally, he's far back of Trump and Cruz in third.

That leads to a concern on the minds of many in the Republican political establishment: Which early state can he actually win? His campaign is counting on a long slog, but such a path to the nomination would be unprecedented.

3. Ted Cruz, Republican, senator from Texas

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Sen. Ted Cruz (R-Texas)

From November to December, Cruz jumped 7 points nationally, 15 points in Iowa, and 8 points in South Carolina.

But a war with Trump -- something he had stressed he would not do -- has started to take a bit of a toll in the first-caucus state of Iowa. After taking the lead from Trump there last month, Trump has leapfrogged Cruz to take back front-running status in the Hawkeye State.

Still, Cruz's under-the-radar campaign has put him in sneakily good position to capture the nomination. And his eye-popping fund-raising numbers mean he will most likely be in the race for the long haul.

Cruz inspires a flood of enthusiasm among the GOP base, and he may be the best-positioned candidate from within the political sphere to back up the notion that he's not a typical politician, that he is the outsider the base wants despite his day job in Washington.

National polling average among Republican voters: 19.3% (2nd)

Iowa: 27.5% (2nd)

New Hampshire: 13.3% (2nd)

South Carolina: 19.5% (2nd)

STOCK: Neutral

Last month: 3

2. Donald Trump, Republican, businessman

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Trump has lit the political world on fire since his entry into the race early this summer. And he has showed surprising staying power -- we're now on month No. 8 of the Trump show.

The summer of Trump, which turned into the autumn of Trump, has become the winter of Trump. And he's perhaps in his strongest position yet, seemingly primed to capture the first-four voting states of Iowa, New Hampshire, South Carolina, and Nevada.

There's a clear appetite among Republican primary voters for someone like Trump, who entered the race to controversy surrounding his position on illegal immigration. Business Insider discovered more of that when we followed him on the trail for a week last year.

1. Hillary Clinton, Democrat, former secretary of state

Clinton is No. 1 here because she has proved formidable in polling and fund-raising and has a clearer path to the nomination than anyone on the GOP side.

But Clinton enters the election facing perhaps the biggest challenge to her candidacy.

The summer provided sign after sign of her potential vulnerabilities as a candidate. She saw Sanders sap enthusiasm — and supporters — in key early states like Iowa and, especially, New Hampshire. Her popularity plunged. And she trailed a host of leading Republican candidates in theoretical general-election matchups.

She turned things around in the fall. She was up overwhelmingly in Iowa.

That's no longer the case. Sanders could hand Clinton her second shocking loss in a row in the Hawkeye State, and he looks primed to win in the Granite State. In that case, Clinton will have to hope her 'firewall' — her strength in states with more diverse Democratic electorates — holds up.
National polling average among Democratic voters: 52.5% (1st)
Iowa: 45.8% (2nd)
New Hampshire: 38.6% (2nd)
South Carolina: 62.5% (1st)

STOCK: Neutral
Last month: 1

And to the polls: Here's a look at where the candidates stand in their respective parties in a combined average of national, New Hampshire, Iowa, and South Carolina polls.